Merge "Set SCSI as the default cdrom bus for PowerKVM"

nova/tests/virt/libvirt/test_libvirt_blockinfo.py

@@ -547,16 +547,22 @@ class LibvirtBlockInfoTest(test.TestCase):
                          block_device_info['block_device_mapping'][0])
 
     def test_get_disk_bus(self):
-        bus = blockinfo.get_disk_bus_for_device_type('kvm')
-        self.assertEqual(bus, 'virtio')
-
-        bus = blockinfo.get_disk_bus_for_device_type('kvm',
-                                                     device_type='cdrom')
-        self.assertEqual(bus, 'ide')
-
-        bus = blockinfo.get_disk_bus_for_device_type('kvm',
-                                                     device_type='floppy')
-        self.assertEqual(bus, 'fdc')
+        expected = (
+                ('x86_64', 'disk', 'virtio'),
+                ('x86_64', 'cdrom', 'ide'),
+                ('x86_64', 'floppy', 'fdc'),
+                ('ppc', 'disk', 'virtio'),
+                ('ppc', 'cdrom', 'scsi'),
+                ('ppc64', 'disk', 'virtio'),
+                ('ppc64', 'cdrom', 'scsi')
+                )
+        for arch, dev, res in expected:
+            with mock.patch.object(blockinfo.libvirt_utils,
+                                   'get_arch',
+                                   return_value=arch):
+                bus = blockinfo.get_disk_bus_for_device_type('kvm',
+                            device_type=dev)
+                self.assertEqual(bus, res)
 
         image_meta = {'properties': {'hw_disk_bus': 'scsi'}}
         bus = blockinfo.get_disk_bus_for_device_type('kvm',

nova/virt/libvirt/blockinfo.py

@@ -81,7 +81,7 @@ from nova.openstack.common.gettextutils import _
 from nova.virt import block_device as driver_block_device
 from nova.virt import configdrive
 from nova.virt import driver
-
+from nova.virt.libvirt import utils as libvirt_utils
 
 CONF = cfg.CONF
 
@@ -217,6 +217,7 @@ def get_disk_bus_for_device_type(virt_type,
        type, return the optimal disk_bus to use for a given
        device type. For example, for a disk on KVM it will
        return 'virtio', while for a CDROM it will return 'ide'
+       on x86_64 and 'scsi' on ppc64.
 
        Returns the disk_bus, or returns None if the device
        type is not supported for this virtualization
@@ -245,7 +246,11 @@ def get_disk_bus_for_device_type(virt_type,
             return "xen"
     elif virt_type in ("qemu", "kvm"):
         if device_type == "cdrom":
-            return "ide"
+            arch = libvirt_utils.get_arch(image_meta)
+            if arch in ("ppc", "ppc64"):
+                return "scsi"
+            else:
+                return "ide"
         elif device_type == "disk":
             return "virtio"
         elif device_type == "floppy":

nova/virt/libvirt/utils.py

@@ -20,6 +20,7 @@
 
 import errno
 import os
+import platform
 
 from lxml import etree
 from oslo.config import cfg
@@ -653,3 +654,23 @@ def get_instance_path(instance, forceold=False, relative=False):
     if relative:
         return instance['uuid']
     return os.path.join(CONF.instances_path, instance['uuid'])
+
+
+def get_arch(image_meta):
+    """Determine the architecture of the guest (or host).
+
+    This method determines the CPU architecture that must be supported by
+    the hypervisor. It gets the (guest) arch info from image_meta properties,
+    and it will fallback to the nova-compute (host) arch if no architecture
+    info is provided in image_meta.
+
+    :param image_meta: the metadata associated with the instance image
+
+    :returns: guest (or host) architecture
+    """
+    if image_meta:
+        arch = image_meta.get('properties', {}).get('architecture')
+        if arch is not None:
+            return arch
+
+    return platform.processor()